Resource influence on the form of fur rubbing behaviour in white-faced capuchins

Self-medicative behaviours have been largely documented in vertebrates and, in particular, the use of plants for pharmacological purposes has been mainly reported in primates. White-faced capuchins are known to rub specifically chosen plants and other substances on their fur. To better understand the mechanisms underlying this phenomenon and investigate the influence of different plant resources on the form of fur rubbing activity, we conducted experiments using different randomly selected plant items: oranges and onions. We found that (1) capuchins showed different degrees of interest in the materials used to fur rub; (2) the mean group dynamics differ drastically according to the resource supplied; and (3) individuals present strong differences in their social behaviour, i.e. they spent more or less time fur rubbing in spatial proximity of conspecifics according to the material used for fur rubbing. We propose hypotheses on possible proximal causes for these differences and highlight that some precautions have to be taken in behavioural studies including only one resource type.